Electrode consumption indicator



y 1965 AL KONCEWICZ ELECTRODE CONSUMPTION INDICATOR 2 Sheets-Sheet 1 Filed Feb. 18, 1963 INVENTOR. Al Koncewicz July 20, 1965 Filed Feb. 18, 1965 AL KONCEWICZ ELECTRODE CONSUMPTION INDICATOR 2 Sheets-Sheet 2 INVENTOR. A l Koncewicz United States Patent "Ce 3,196,361; ELECTRQDE QQNSUMPTHUN HNDHCATGR Al Koncewiez, Henderson, Nev., assignor to Titanium Metals Corporation of America, New York, N.Y., a corporation of Delaware Filed Feb. 18, 1963, Ser. No. 26tl,ll96 7 Claims. (Cl. 314-9) This application is a continuation-in-part of my application Serial No. 131,909 filed August 16, 1961, now abandoned.

This invention relates to the art of consumable electrode are melting equipment; and more particularly to means for indicating the extent of consumption of an electrode being consumed and melted into an ingot in an arc furnace.

Consumable electrode arc melting furnaces are often employed to melt refractory metals including titanium, Zirconium and certain steels. The design and operation of such furnaces are becoming widely known. It is important in consumable electrode melting operations to obtain an indication of the extent to which the electrode has been consumed as melting progresses and particularly at or near the end of the melt. The electrode is not ordinarily completely consumed, but melting is stopped before the heat of the arc can damage the electrode attachments, supports or associated structures. Determination of the end of melt point, or point at which end of melt procedures, such as hot topping, should be initiated is difficult because the furnaces are generally completely enclosed, and often operated under vacuum. Visual methods are not practical, and heretofore proposed electrical and mechanical devices for this purpose have often proved inaccurate, unreliable or complicated, and diflicult to maintain in operating condition.

It is therefore the principal object of this invention to provide improved apparatus for determining the extent to which a consumable electrode in an arc furnace has been consumed. Another object of this invention is to provide simple, efficient and reliable apparatus for indicating the point to which a consumable electrode has been consumed in an arc furnace. These and other objects of this invention will be apparent from the following description thereof and from the annexed drawings in which:

FIG. 1 shows a general view of apparatus embodying features of this invention.

FIG. 2 shows the apparatus of FIG. 1 when the electrode has been consumed to the indicating point.

FIG. 3 shows a general view of a modified form of apparatus embodying feature of this invention.

FIG. 4 shows the apparatus of FIG. 3 when the electrode has been consumed to the indicating point.

Referring now to FIG. 1 the apparatus according to this invention is employed in conjunction with a consumable electrode arc melting furnace whose upper portion contains the electrode driving mechanism, and whose sidewall is shown at 10. Attached to the lower end of sidewall i crucible 12 surrounded by spaced outer shell 14, the inter-space constituting a cooling jacket through which a fiuid such as water may be circulated. An electrode to be melted 16, whose body is formed of welded compact sections 17 is suitably attached as by clamp 18 to support rods 28 which are actuated up and down as required by conventional mechanism (not shown) so as to maintain the required spacing and are conditions between the bottom of electrode 16 and the pool of metal 22 in crucible 12.

A closed bottom vertical hole 24 is provided in the top of electrode 16. Attached, as by welding at 26 to an inside surface as a side or bottom surface of hold 24,

3,1965% Patented July 20, 1965 is the lower end of wire 28. The attachment 26 and wire 28 are preferably of the same material as electrode 16; for example, a titanium wire welded to a titanium electrode using titanium welding rod. In any event, the attachment 26 and wire 28 must be fabricated of material having a melting point at least as high a that of electrode 16. Fabrication of electrode 16 by assembly from a plurality of sections formed of compacted metal particles such as titanium sponge, provides convenient opportunity to provide hole 24 in opposing and mating sections, and convenient welding of the bottom end of wire 28 in place. The attachment of the bottom of wire 28 is made to the electrode 16 at a point at which indication of electrode consumption is desired, and this will be, as will be apparent, when electrode 16 has been consumed, and thereby melted and transferred into crucible 12, up to the plane across the electrode 16 on which lies weld 26.

Wire 28 is maintained under tension by spring 30 which is deformed and compressed as shown between collar 32, attached to the upper end of wire 28, and the bottom of cage 34. Flexible cable 36 i attached at one end to the top of cage 34 and passes over pulleys 33 and 45) which are mounted on bracket 4-2. attached to furnace sidewall 15?. To the other end of flexible cable 36 is attached counterweight 44 so that tension on wire 23 exerted by spring 349 may be maintained even though electrode 16 moves vertically up or down in response to actuation by its driving mechanism. A temporary counterweight support 46 may be provided attached to furnace sidewall 10.

Attached to a side of cage 34 is normally open swich 48 whose actuating arm St is arranged to lie in the path of travel of collar 32 when spring 36 is relaxed and extended. Lead wires 52 and $4 electrically connect switch 48 through sidewall 11 to external indicating means which comprise battery 56 and bell 58.

In operation of the apparatus of FIG. 1 the bottom end of wire 28 is welded in place at 26 to the bottom of a hole forming cavity in one of the electrode sections 17. These sections 17 are then welded together to form electrode 16 which i mounted in the furnace by clamp 18 in melting position. Cable 36 with cage 34 and counterweight 44 are set up as shown in FIG. 1 to maintain wire 28 under tension.

Normal and conventional procedures which will be familiar to those skilled in the art, are employed to initiate and maintain a melting are between the bottom of electrode 16 and the pool of metal 22 in crucible 12, electrode 16 being progressively consumed during the melting process.

Reference to FIG. 2 will show the result of melting and consuming electrode 16 up to the desired indicating point 26. When consumption of electrode 16 has reached the surface of hole 24 where wire 28 is attached at 26, the heat of the arc melts the electrode metal in the area of attachment 26 and may also simultaneously melt the weld itself and thus frees the lower end of wire 28 as shown. Since the lower end of wire 28 is no longer anchored, its tension is relieved and spring 30 relaxes and expands, thus causing collar 3.2 to engage actuating arm 5% of switch 48. This closes the indicating means circuit causing bell 58 to ring to provide audible indication of consumption of electrode 16 to point 26.

Another embodiment of this invention is shown in FlG. 3, the furnace sidewall 10 being the same as in FIGS. 1 and 2, and attached to crucible 12, with outer shell 14 forming a cooling jacket. A solid electrode 59 is attached by clamp 18 to support rods 29. In this embodiment the apparatus, except for the external indicating part, is attached to the electrode clamp 18, thus moving arouses as a unit up or down with the electrode This is accomplished by provision of wire at whose lower end is attached, as by welding at as, to an outer surface of electrode lo and at the point or level where consumption indi- 'tension, as long as its attachment at 62 remains. Switch '72, normally open, is fixedly attached to bracket'7ii with its actuating arm 74 arranged to lie in the path of travel of collar 64 when spring as is relaxed and contracted. Electrical leads 7d and it; connect switch '72 through the sidewall lit with external indicating means which comprise battery 3% and light 82. As with the embodiment previousty described, the wire 6t and its attachment or weld '62 are fabricated of material having a melting point at least as high as that of electrode and are preferably of the same material. 7

Operation of the embodiment of FlG. 3 is similar to that described for the embodiment shown in H6. 1. The wire as is attached to an outer surface of electrode 59 as by welding at 62, the location of weld 62 being at the point or level of electrode at which consumption indication is desired. Melting procedures are initiated and maintained so that the established are progressively melts and consumes electrode 59.

Reference to FIG. 4 will show the result of melting and consuming electrode 59 up to the desired indicating point 62. When consumption of electrode 59 has reached the surface of electrode 59 where wire is attached at es, the heat of the arc melts the electrode metal in the area of attachment 62 and may also simultaneously melt the weld itself and thus frees the lower end of wire 6t? as shown. Since the lower end of wire/6d is no longer anchored, its tension is relieved and spring (so relaxes and contracts thus causing collar 64 to engage actuating arm 74 or" switch 72. This closes the indicating means circuit causing light 82 to light up to provide visible indication of consumption of electrode 16 to point 62.

The apparatus of this invention is useful to provide end of melt indication, or to indicate the time for initiating hot topping procedure, when melting metallic electrodes in a consumable electrode arc furnace. If desired, the electrical circuit operating the indicating means may be connected to suitable apparatus for shutting oil or altering the amount of electric current supplied to the arc in the furnace. Thus, automatic shutting oil or altering the amount of power supplied to the arc may itself be used as an indication of electrode consumption to the point of wire attachment, or such current control may be employed in conjunction with an indicator such as a bell,

light or the like. The apparatus is simple and inexpensive, while itsoperation is positive and reliable.

The apparatus of this invention provides positive indi cation of consumption of an electrode to a predetermined point, because the wire connecting the indicating means to the electrode remains in set position and gives no signal until the electrode itself is melted to the point of at tachment, thus destroying the attachment itself. The action is thus wholly direct and also simple and reliable.

The actuating wire and its attachment or weld to the electrode must be of material having a melting point at least at high as the electrode to avoid melting of these elements before the electrode has been melted to the attachment point which could give a premature and false indication of electrode consumption. It will be seen that the actuating mechanism inside the furnace contains no low melting point or fusible links, plugs or attachments which can themselves melt to actuate the syst The wire attachment is destroyed only when the electrode has itself been melted to the attachment point.

Preferably the wire and its attachment or weld to the electrode should be of the same material as the electrode. 5 This automatically insures that these will not melt before the electrode has melted to the indicating point to give a premature signal. This also insures that the ingot pro duced will not be contaminated should any part of the wire or its attachment fall into, or after or at signal indication become melted and fall into, the pool of molten metal under the electrode.

1 claim:

ll. Apparatus for indicating the extent of consumption 'of an electrode in a consumable electrode arc furnace which comprises;

(a) a wire having its lower end attached to said electrode at a point at which consumption indication is desired, said wire and its attachment to said electrode being of material having a melting point at least as high as the material of said electrode,

(b) means for applying tension to said wire,

(c) a switch responsive to relief of tension applied to said wire when the attachment of the lower end of said wire to said electrode is destroyed by consumption of said electrode to the wire attachment point, and,

((1) indicating means electrically connected to and corn trolled by said switch.

2. Apparatus for indicating the extent of consumption of an electrode in a consumable electrode arc furnace which comprises;

(a) a wire having its lower end attached to said electrode at a point at which consumption indication is desired, saidwire and its attachment to said electrode being of the same material as that of said electrode,

(b) means for applying tension to said wire,

(c) a switch responsive to relief of tension applied to said wire when the attachment of the lower end of said wire to said electrode is destroyed by consumption of said electrode to the wire attachment point, and,

(d) indicating means electrically connected to and controlled by said switch.

3 Apparatus for indicating the extent of consumption of an electrode in a consumable electrode arc furnace which comprises;

(a) a wire having its lower end attached to an inside surface of a vertical closed-bottom hole in the top of said'electrode' at a point at which consumption indication is desired, said wire and its attachment to said electrode being of material having a melting point at least as high as the material of said electrode,

(b) means for applying tension to said wire,

(c) a switch responsive to relief of tension applied to said wire when the attachment of the lower end of said wire to said electrode is destroyed by consumption of said electrode to the wire attachment point, and, i

(d) indicating means electrically connected to and controlled by said switch.

l. Apparatusfor indicating the extent of consumption of an electrode in a consumable electrode arc furnace which comprises;

(a) a wire'having its lower end attached to said electrode at a point at which consumption indication is desired, said wire and its attachment to said electrode being of material having a melting point at least as high as the material of said electrode,

(b) a deformed spring attached to the other end of said wire and applying tension to said wire,

(0) a switch responsive to relaxation of said spring and relief of tension applied to said wire when the attachmfini O t e lower end of said wire to said elec trode is destroyed by consumption of said electrode to the wire attachment point, and,

(d) indicating means electrically connected to and controlled by said switch.

5. Apparatus for indicating the extent of consumption of an electrode in a consumable electrode arc furnace which comprises;

(a) a wire having its lower end attached to said electrode at a point at which consumption indication is desired, said wire and its attachment to said electrode being of material having a melting point at least as high as the material of said electrode,

(b) a compressed spring attached to the other end of said Wire and applying tension to said wire,

() a switch responsive to expansion of said spring and relief of tension applied to said Wire when the attachmerit of the lower end of said wire to said electrode is destroyed by consumption of said electrode to the wire attachment point, and,

((1) indicating means electrically connected to and conitrolled by said switch.

6. Apparatus for indicating the extent of consumption of an electrode in a consumable electrode arc furnace which comprises;

(a) a wire having its lower end attached to said electrode at a point at which consumption indication is desired, said wire and its attachment to said electrode being of material having a melting point at least as high as the material of said electrode,

(b) an expanded spring attached to the other end of said wire and applying tension to said wire,

(c) a switch responsive to contraction of said spring and relief of tension applied to said wire when the attachment of the lower end of said wire to said elecrode is destroyed by consumption of said electrode to the wire attachment point, and,

((1) indicating means electrically connected to and controlled by said switch.

7. Apparatus for indicating the extent of consumption or: an electrode in a consumable electrode arc furnace which comprises;

(a) a Wire having its lower end attached to said electrode at a point at which consumption indication is desired, said wire and its attachment to said electrode being of material having a melting point at least as high as the material of said electrode,

(b) means for applying tension to said wire,

(c) a switch responsive to relief of tension applied to said wire when the attachment of the lower end of said wire to said electrode is destroyed by consumption of said electrode to the wire attachment point, and,

(d) indicating means external of said consumable electrode arc furnace electrically connected to and controlled by said switch.

Reierences Cited by the Examiner UNITED STATES PATENTS 218,375 8/79 Fuller 3l4-10 501,081 7/93 Kirkegaard 314-10 502,465 8/93 Mehren 314-10 2,762,856 9/56 Newcomb et al. 13-9 RICHARD M. WOOD, Primary Examiner. JOSEPH V. TRUHE, Examiner. 

1. APPARATUS FOR INDICATING THE EXTENT OF CONSUMPTION OF AN ELECTRODE IN A CONSUMABLE ELECTRODE ARC FURNACE WHICH COMPRISES; (A) A WIRE HAVING ITS LOWER END ATTACHED TO SAID ELECTRODE AT A POINT AT WHICH CONSUMPTION INDICATION IS DESIRED, SAID WIRE AND ITS ATTACHMENT OT SAID ELECTRODE BEING OF MATERIAL HAVING A MELTING POINT AT LEAST AS HIGH AS THE MATERIAL OF SAID ELECTRODE, (B) MEANS FOR APPLYING TENSION TO SAID WIRE, (C) A SWITCH RESPONSIVE TO RELIEF OF TENSION APPLIED TO SAID WIRE WHEN THE ATTACHMENT OF THE LOWER END OD SAID WIRE TO SAID ELECTRODE IS DESTROYED BY CONSUMPTION OF SAID ELECTRODE TO THE WIRE ATTACHMENT POINT, AND, (D) INDICATING MEANS ELECTRICALLY CONNECTED TO AND CONTROLLED BY SAID SWITCH . 